A tire support for a vehicle tire is a support suitable for being mounted on a wheel rim inside of a tire. A tire support is a precautionary device against a tire losing air pressure, and it is intended to bear the weight of a vehicle if a tire loses partial or total air pressure to the extent that loss of vehicle control or irreparable damage to the tire might occur by continued use of the vehicle without the tire support. Tire supports are known and described in, for example, U.S. Pat. No. 5,891,279.
A tire support is desirable because it can replace a spare tire to enable a vehicle to continue traveling to a service facility where inflation, repair, or replacement of an at least partially-deflated tire can be accomplished. This is advantageous for improving vehicle storage space by removing the necessity for storing a spare tire and a jack, for reducing the overall weight of a vehicle to improve fuel economy, and for reducing the likelihood of additional vehicle damage when a vehicle continues after a tire loses air pressure.
A tire support can be prepared by molding a polymeric material in a device, i.e., a mold, configured for a tire support. Examples of molding processes that have been used include centrifugal molding and reaction injection molding (RIM). Centrifugal molding is typically less than desirable for preparing a tire support because it can be prohibitively expensive for commercial application. For example, centrifugal molding can require extended processing times.
RIM is typically more desirable for processing a tire support because RIM can require less processing time than centrifugal molding, which can decrease production cost.
Processing times for centrifugal molding or RIM molding can be affected by how easily a tire support can be removed from a mold. For example, it may be difficult to remove a tire support from a mold because portions of the tire support may constrict against a mold surface as well as pull away from another mold surface due to the material shrinking as it sets or cures. This can slow down production, subsequently increasing production expense. Similarly, a tire support can indiscriminately stick to an upper or lower portion of a mold when the upper and lower portions are separated. Not only can this slow down production, but it can result in a damaged tire support if a tire support remains with the upper portion during separation and then later releases from the upper portion, subsequently striking the lower portion of the mold, floor, or both.
Thus, it is desirable to develop a method and a device that facilitate release of a tire support from a mold.